Measurements of Cross Sections for Single and Double Ionization of Na+ and K+ by Electron Impact

Cross sections for single and double ionization of K + and Na + by electron impact have been measured as a function of electron energy from their respective threshold to approximately 1500 eV with the use of the electron-ion crossed-beam technique. The results for single ionization of Na + and K + are in good agreement with the previous crossed-beam data within the experimental uncertainties. Contributions from an autoionization and an L-shell direct ionization followed by autoionization (Auger effect) have been found in the results of single and double ionization cross sections for K + .